Abstract: Drying-wetting cycle usually occurs in compacted embankment fill due to periodic variation in precipitation and evaporation, which affects the long-term stability of embankment and subgrade. A series of compression tests are performed to measure the variation in vertical compression strain of compacted loess subjected to cyclic drying-wetting by using pneumatic oedometer apparatus so as to study the effect of drying-wetting cycle on deformation behaviors. The relationships between vertical compression strain and vertical pressure ( - ) at different initial compaction degrees are fitted with the existing models; and the relationships between secant modulus and as well as number of drying-wetting cycle are established. The results show that of compacted loess tend to increase with numbers of drying-wetting cycles and then keep fairly stable after 5-7 cycles; Moreover, the increment of remarkably affect by . The - curve of compacted loess can be depicted by the Gunary model exactly under uniaxial compression condition, and its behaviors are unchanged due to repeated drying-wetting cycle; The relationship between and as well as also can be formulated in exponential form without considering the effect of water content. It can be concluded that the change in deformation behaviors is irreversible after the compacted loess is subjected to drying-wetting cycle.

Key words: compacted loess, drying-wetting cycle, vertical compression strain, vertical pressure, secant modulus